The present invention relates to high-pressure fluid delivery systems and more particularly to an improved safety conduit for use in high-pressure fluid delivery systems.
As described in U.S. Pat. No. 5,357,998, which is incorporated by reference herein, there is a risk of conduit failure when working with fluids traveling through fluid conduits. Conduit failure can occur in high-pressure and low pressure situations.
When filling containers (which includes, but is not limited to, cylinders, tank trucks, rail cars, and stationary tanks) with compressed or non-compresses gasses or fluids, or operating equipment that relies on pressurized fluid flow or compressed gas, it is necessary for the fluid/gas to be transferred from one container to another. Although the fluid/gas can be transferred from one container to another using solid piping, it is common in many situations to use a flexible conduit or hose attached between the containers. A flexible hose allows ease of connection/disconnection of containers, as well as a limited range of motion between source and destination.
For example, compressed or non-compresses fluid/gas, such as oxygen, nitrogen, carbon dioxide and chemicals, such as petroleum and acids are transported, stored and used in individual containers of varying size and capacity. In order to fill these containers with the desired product, it is necessary to connect each container to a filling connection (either singly or in groups) at the location of a gas filler/seller. In order to connect each container to the filling connection, a flexible hose is used to allow for quick connection/disconnection of the containers to the filling connection. A filling station manifold is one example of a filling connection. In addition, operating equipment that runs or uses compressed gas (such as forklifts) or pressurized fluids (such as hydraulic systems) also benefit from the ease of use of flexible hose.
Hoses can fail, however, even though they are generally made from durable yet flexible materials/constructions, such as treated and reinforced rubber, neoprene, nylon, TEFLON(trademark), stainless steel and others. Hose failures can occur from a number of causes, including ruptures, deteriorations and splits/cuts. When a hose fails, it can cause substantial damage in a number of ways. First, if a hose is completely severed or split, both ends of the hose can whip around wildly under the forces of the compressed gas or fluid, now exerted from the delivery end and the receiving end. In addition, if a container is not secured, the pressure of the gas or fluid leaving the container can cause the container to move very rapidly in the opposite direction of the gas/fluid. Both of these situations can result in substantial risk of personal injury, as well as property damage. Still further, a hose failure will cause a leak from both the delivery and receiving ends, leading to a costly waste of gas or fluid, the discharge of hazardous gas or fluids, as well as the by potential of filling the environment with hazardous fumes.
U.S. Pat. No. 5,357,998 discloses a successful fluid conduit safety system that uses a flexible, yet relatively stiff cable disposed inside of a hose to maintain single valve bodies at either end of the hose in an open position during normal or open operation. When a failure condition, such as a rupture, cut, separation or stretch of the hose occurs, the valve bodies are able to seat with the valve seats, sealing both ends of the hose. This prevents fluid/gas leaks from both sources (i.e. container and filling apparatus). When a failure occurs, the flexible, yet relatively stiff cable may be severed, allowing the fluid pressure to force the valve bodies into engagement with the valve seats. If a hose failure does not sever the cable, the valve seats are either forced into engagement with the valve bodies or the valve bodies are forced into engagement with the valve seats. In either circumstance, a seal is accomplished by seating the valve bodies with the valve seats.
The present invention involves a safety system for a fluid conduit comprising a fluid conduit having first and second ends, first and second housings attached to said fluid conduit at the respective first and second ends, a first valve seat disposed in the first housing and a second valve seat disposed in the second housing. The first and second valve seats are positioned a first predetermined distance from each other. A first valve body is disposed in the first housing at the first end of the conduit and a second valve body is disposed in the second housing at the second end of the conduit. The first and second valve seats are disposed between the first and second valve bodies, with the first and second valve bodies positioned a second predetermined distance from the first and second valve seats, respectively. A valve control means retains the first and second valve bodies the second predetermined distance from the first and second valve seats, respectively, during an open flow condition, and seats one or both of the first and second plurality of valve bodies with the first and second valve seats, respectively, during a conduit failure.